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Land degradation resulting from soil salinization is becoming a growing menace in almost all over the world. The degraded soil shows poor performance in water conductance and soil aeration, which threatens plant growth and development. Therefore, to discover the resistance genes and breed plant with stress tolerance are necessary. The modern molecular biotechnology makes the plant with enhanced adaption possible. To do this, KvHSP70 with 1950 bp open reading frame (ORF) from Kosteletzkya virginica was isolated, studied, and transformed into tobacco for functional study. Our research showed that it encodes a typical HSP70 protein with 649 amino acids and it could be induced by salt, high temperature, drought, and abscisic acid (ABA). The transgenic tobacco with it overexpression had higher chlorophyll content, less electrolyte leakage, lower water potential and increased proline content under salt stress. Meanwhile, the transgenic acquired superior antioxidant enzyme activities and decreased MDA content. All results highlight the significance of the new found gene in breeding salt resistant plants with molecular manipulation. Hence, K. virginica provides us with helpful information and gene resources to culture new variety adapted to salt‐affected soil and available for land rehabilitation perhaps in the future.

In higher plants, aquaporin proteins (AQPs) play important roles in the uptake of water across cell membranes. However, their functions in halophytes are still largely unknown. In this work, we isolated, cloned, and identified KvTIP3, a tonoplast intrinsic protein gene from Kosteletzkya virginica. Bioinformatic analyses demonstrated that KvTIP3 encoded a tonoplast protein with the common properties of AQPs. Further multiple sequence alignment and phylogenetic analyses showed that KvTIP3 shared 65%–82% homology with other AQPs from Arabidopsis, cotton, polar, and cocoa. Quantitative real-time PCR (qPCR) analyses revealed that KvTIP3 was ubiquitously expressed in various tissues such as leaves, stems, and roots, with a predominant expression in roots. In addition, KvTIP3 transcript was strongly induced by NaCl, low temperature, and ABA in K. virginica. Our findings suggest that KvTIP3 encodes a new AQP possibly involved in multiple abiotic stress responses in K. virginica, and KvTIP3 could be used as a potential candidate gene for the improvement of plants resistant to various abiotic stresses.

Small heat shock proteins (sHSPs) are a group of chaperone proteins existed in all organisms. The functions of sHSPs in heat and abiotic stress responses in many glycophyte plants have been studied. However, their possible roles in halophyte plants are still largely known. In this work, a putative sHSP gene KvHSP26 was cloned from K. virginica. Bioinformatics analyses revealed that KvHSP26 encoded a chloroplastic protein with the typical features of sHSPs. Amino acid sequence alignment and phylogenetic analysis demonstrated that KvHSP26 shared 30%-77% homology with other sHSPs from Arabidopsis, cotton, durian, salvia, and soybean. Quantitative real-time PCR (qPCR) assays exhibited that KvHSP26 was constitutively expressed in different tissues such as leaves, stems, and roots, with a relatively higher expression in leaves. Furthermore, expression of KvHSP26 was strongly induced by salt, heat, osmotic stress, and ABA in K. virginica. All these results suggest that KvHSP26 encodes a new sHSP, which is involved in multiple abiotic stress responses in K. virginica, and it has a great potential to be used as a candidate gene for the breeding of plants with improved tolerances to various abiotic stresses.

A comprehensive understanding of the relationship between arbuscular mycorrhizal (AM) fungi and coastal saline soil organic carbon (SOC) is crucial for analysis of the function of coastal wetlands in soil carbon sequestration. In a field experiment, the temporal and spatial dynamics of AM fungi, glomalin-related soil protein (GRSP) – which is described as a N-linked glycoprotein and the putative gene product of AM fungi, SOC, and soil aggregates were investigated in halophyte Kosteletzkya virginica rhizosphere soil of coastal saline areas of North Jiangsu, China. Soil samples were collected from a depth of up to 30 cm in two plantation regions from August 2012 to May 2013. Results showed K. virginica formed a strong symbiotic relationship to AM fungi. AM colonization and spore density were the highest in the 10–20 cm soil layer of Jinhai farm in August 2012, because of the presence of numerous fibrous roots in this soil layer. The total GRSP and SOC were the highest in the 0–10 cm soil layer in May 2013 and November 2012, respectively. Correlation coefficient analysis revealed that AM colonization and spore density were positively correlated with total GRSP. Meanwhile, total GRSP was significantly positively correlated with large macroaggregates (>3 mm), SOC, total P, Olsen P, and soil microbial biomass carbon (SMBC), but negatively correlated with microaggregates (

Vacuolar Na+/H+ antiporters (NHXs) play an important role in plant salt tolerance and a large number of NHX genes have been identified in many plant species. In this study, we isolated and characterized a novel vacuolar-type KvNHX1 cDNA from the halophyte Kosteletzkya virginica. It is 2047 bp long, with an open reading frame of 1632 bp, encoding a protein of 543 amino acids with a theoretical molecular weight of 60.03 kDa. Bioinformatics and phylogenetic analysis showed that it was highly similar to the known vacuolar-type NHXs, especially with 92% identity with GhNHX1 of Gossypium hirsutum from the same Malvaceae family. Quantitative RT-PCR showed that the expression analysis of KvNHX1was significantly increased by NaCl, abscisic acid (ABA) and polyethylene glycol (PEG), but its expression levels and patterns differed under different abiotic stresses, implying that KvNHX1 might be involved in various abiotic stress responses. In addition, overexpression of KvNHX1 enhanced the salt tolerance in transgenic tobacco lines with better growth, more chlorophyll, higher antioxidant enzyme activities and osmoregulation capability by accumulating more proline, Na+ and K+ in the leaves than the wild type under salt stress. Our result suggested that KvNHX1 may have potential use for improving the salt tolerance of plants via genetic engineering.

The financial and technical aspects of using edible plants as a biodiesel source have been studied extensively, but research on the potential use of salt resistant, non-edible plants for this purpose remains relatively underexplored. Data available on salt tolerance range, seed oil content, composition of fatty acid methyl esters (FAME) and engine performance parameters – Iodine Value (IV), Cetane Number (CN) and Saponification Number (SN) – of 20 salt-resistant plants were examined to assess their suitability for use as diesel engine fuel. Most of the test species were perennial from family Amaranthaceae, exhibiting high salt tolerance. The quantity of their seed oil ranged from 10–30% while nine species contained >25% oil. The SN, IV and CN values varied from 130–206, 29–156 and 38–81, respectively. Based on the above mentioned parameters, seven halophytic plant species – Salicornia fruticosa, Cressa cretica, Arthrocnemum macrostachyum, Alhagi maurorum, Halogeton glomeratus, Kosteletzkya virginica and A...

In recent literature, seashore mallow (Kosteletzkya pentacarpos; also known previously as Kosteletzkya virginica) seed oil was reported as a potential alternative feedstock for biodiesel. In the present work, the fatty acid profile of K. pentacarpos is shown to correspond to that of other plants in the Malvaceae family by containing approximately 6% fatty acids with cyclic moieties, namely malvalic acid as well as dihydrosterculic acid. Previously determined properties of biodiesel from seashore mallow are discussed under the aspect of the fatty acid profile. The 1H- and 13C-NMR spectra of K. pentacarpos methyl esters, which confirm the fatty acid profile, are also discussed. Practical applications: This article discusses the fatty acid profile of the seed oils of Kosteletzkya species. This is significant for evaluating potential applications of these oils. This is demonstrated by evaluating biodiesel fuel properties from the results. The seed oils of Kosteletzkya species contain malvalic acid and other acids with cyclic moieties.

Over the past 20 years since its introduction, Kosteletzkya virginica has proved to be one of the optimal halophytes for saline land restoration in China. In six seashore mallow plantations, its well-developed perennial root system promoted the growth of arbuscular mycorrhizal fungus in the rhizosphere, where the fungus’s activity produced total glomalin (TG, ranging from 0.85 to 2.43 mg g −1 soil), with a high ratio of TG/SOC (soil organic carbon) up to 53.29% in six-year-old seashore mallow plantation. K. virginica ameliorated the condition of saline soils, promoted native species growth, and increased plant diversity in the plantation sites. Seashore mallow contains many bioactive compounds, e.g., polysaccharides, saponins, flavonoids, etc. which have high bioactivity, and could be used as a fodder additive or for the development of health foods. The leaf, flower, stem and root of K. virginica , serve as raw materials for hierachical development of useful products according to their different properties. This study reviews and summarizes research on K. virginica in China during the past 20 years since its introduction from the USA. Also, we present guidelines for the planting and use of seashore mallow in China, in terms of an ecological engineering roadmap, which illustrates the process and strategy for the restoration of saline soils and designs for biomass industries based on its production.

Salt stress, with nutrient deficiency, has been threatening plant growth in coastal saline soil. This study is to address the potential of using biochar treated with 1.69 mol/L HNO3 (BCH) as a soil amendment to ameliorate coastal saline soil. Both BCH and BCH with fertilizer treatments increased plant height and biomass of sesbania (Sesbania cannabina) and seashore mallow (Kosteletzkya virginica), especially at the adding rate of 1.5% (w/w). The maximal biomass of sesbania and mallow was increased by 158%, and 214%, respectively. However, with the increasing adding rate, the value of biomass and height for both plant decreased, but not lower than those of the control. It suggested that the biochar treated by HNO3 is a good way to overcome biochar’s inherent nutrient deficiency and ameliorate the soils with salt stress.

The effects of an arbuscular mycorrhizal (AM) fungus, Glomus mosseae, and a phosphate-solubilizing microorganism (PSM), Mortierella sp., and their interactions, on nutrient (N, P and K) uptake and the ionic composition of different root tissues of the halophyte Kosteletzkya virginica (L.), cultured with or without NaCl, were evaluated. Plant biomass, AM colonization and PSM populations were also assessed. Salt stress adversely affected plant nutrient acquisition, especially root P and K, resulting in an important reduction in shoot dry biomass. Inoculation of the AM fungus or/and PSM strongly promoted AM colonization, PSM populations, plant dry biomass, root/shoot dry weight ratio and nutrient uptake by K. virginica, regardless of salinity level. Ion accumulation in root tissues was inhibited by salt stress. However, dual inoculation of the AM fungus and PSM significantly enhanced ion (e.g., Na(+), Cl(-), K(+), Ca(2+), Mg(2+)) accumulation in different root tissues, and maintained lower Na(+)/K(+) and Ca(2+)/Mg(2+) ratios and a higher Na(+)/Ca(2+) ratio, compared to non-inoculated plants under 100 mM NaCl conditions. Correlation coefficient analysis demonstrated that plant (shoot or root) dry biomass correlated positively with plant nutrient uptake and ion (e.g., Na(+), K(+), Mg(2+) and Cl(-)) concentrations of different root tissues, and correlated negatively with Na(+)/K(+) ratios in the epidermis and cortex. Simultaneously, root/shoot dry weight ratio correlated positively with Na(+)/Ca(2+) ratios in most root tissues. These findings suggest that combined AM fungus and PSM inoculation alleviates the deleterious effects of salt on plant growth by enabling greater nutrient (e.g., P, N and K) absorption, higher accumulation of Na(+), K(+), Mg(2+) and Cl(-) in different root tissues, and maintenance of lower root Na(+)/K(+) and higher Na(+)/Ca(2+) ratios when salinity is within acceptable limits.

The LEA proteins are a kind of hydrophilic proteins, playing main functions in desiccation tolerance. However, their importance as a kind of stress proteins in abiotic stress is being clarified little by little. In this study we isolated, cloned, and identified the firstKvLEAgene inKosteletzkya virginica. Bioinformatic analysis showed that the protein encoded by this gene had common properties of LEA proteins and the multiple sequences alignment and phylogenetic analysis further showed that this protein had high homology with twoArabidopsisLEA proteins. Gene expression analysis revealed that this gene had a higher expression in root and it was induced obviously by salt stress. Moreover, the transcripts ofKvLEAwere also induced by other abiotic stresses including drought, high temperature, chilling, and ABA treatment. Among these abiotic stresses, ABA treatment brought about the biggest changes to this gene. Collectively, our research discovered a novel LEA gene and uncovered its involvement in multiabiotic stresses inK. virginica. This research not only enriched studies on LEA gene in plant but also would accelerate more studies onK. virginicain the future.

Salt marshes constitute major sinks for heavy metal accumulation but the precise impact of salinity on heavy metal toxicity for halophyte plant species remains largely unknown. Young seedlings of Kosteletzkya virginica were exposed during 3 weeks in nutrient solution to Cd 5 µM in the presence or absence of 50 mM NaCl. Cadmium (Cd) reduced growth and shoot water content and had major detrimental effect on maximum quantum efficiency (F(v) /F(m) ), effective quantum yield of photosystem II (Y(II)) and electron transport rates (ETRs). Cd induced an oxidative stress in relation to an increase in O(2) (•-) and H(2) O(2) concentration and lead to a decrease in endogenous glutathione (GSH) and α-tocopherol in the leaves. Cd not only increased leaf zeatin and zeatin riboside concentration but also increased the senescing compounds 1-aminocyclopropane-1-carboxylic acid (ACC) and abscisic acid (ABA). Salinity reduced Cd accumulation already after 1 week of stress but was unable to restore shoot growth and thus did not induce any dilution effect. Salinity delayed the Cd-induced leaf senescence: NaCl reduced the deleterious impact of Cd on photosynthesis apparatus through an improvement of F(v) /F(m) , Y(II) and ETR. Salt reduced oxidative stress in Cd-treated plants through an increase in GSH, α-tocopherol and ascorbic acid synthesis and an increase in glutathione reductase (EC 1.6.4.2) activity. Additional salt reduced ACC and ABA accumulation in Cd+NaCl-treated leaves comparing to Cd alone. It is concluded that salinity affords efficient protection against Cd to the halophyte species K. virginica, in relation to an improved management of oxidative stress and hormonal status.

Hydroponic experiments were carried out using seedlings of the wetland halophyte species Kosteletzkya virginica (L.) Presl. exposed to 10 μM Cd or 100 μM Zn in the absence or presence of 50 mM NaCl. Interaction between salinity and heavy metals was analysed in relation to plant growth, water status and tissue ion contents (Na, K and Ca). Results showed a strong inhibition effect of Cd on leaf emergence, lateral branch development and leaf expansion. Heavy metals induced a significant decrease in plant dry weight, water content, osmotic potential (Ψ S) and leaf water potential (Ψ w). Cadmium and Zn accumulated to higher extent in the roots than in the shoots. Cadmium increased the leaf K concentration while Zn had an opposite effect. Salinity strongly reduced Cd uptake and translocation from roots to shoots: it mitigated the Cd impact on lateral branch emergence but had no effects on plant dry weight and water status. Cadmium drastically reduced Na translocation in salt-treated plants while Zn increased it. It is concluded that complex interactions exist between heavy metals and monovalent cations in salt conditions and that Cd and Zn display contrasting behaviour in this respect. Stress-induced modification of ion content did not fully explain growth inhibition in Kosteletzkya virginica.

Kosteletzkya pentacarpos (L.) Ledeb. (syn. = Kosteletzkya virginica (L.) C. Presl ex A. Gray) has been treated as a single variable species or as a species including four varieties: K. virginica var. althaeifolia, var. aquilonia, var. smilacifolia, and var. virginica. The aim of this study was to test the validity of formally recognizing these putative infraspecific taxa with a statistical analysis of morphological data. Loans were received from 15 herbaria, for 1,114 specimens; 224 were selected. Measurements were taken from these 224 specimens for 42 characters and analyzed by canonical discriminant analysis, which recognized two dimensions. Var. smilacifolia and var. aquilonia were separated from the other two groupings and correctly predicted at 100%. Var. smilacifolia is morphologically distinct from the other taxa in having linear hastate leaves with reflexed linear lobes, an unbranched inflorescence, a slender stem, and a mostly entire leaf margin. A new combination is proposed: Kostelet...

In this paper, the bast of the Kosteletzkya virginica are degummed and separated into fine fibers, the chemical composition, morphology, microstructure and mechanical properties of the Kosteletzkya virginica bast fibers are characterized by means of SEM, ART-FTIR, DSC-TGA, XRD and Instron tensile tester. The results show that the surface of the Kosteletzkya virginica bast fibers is smooth, and there are many visible grooves along the vertical section. Typical cellulose I in the Kosteletzkya virginica bast fibers is confirmed by FTIR and XRD analysis. The crystallinity of the Kosteletzkya virginica bast fibers is higher than that of the cotton fibers and lower than that of the castor-oil plant bast fibers. The beginning and maximum decomposition temperature of the Kosteletzkya virginica bast fibers are 252 and 347 °C respectively, which indicate that the Kosteletzkya virginica bast fibers have an appropriate thermal stability. The Kosteletzkya virginica bast fibers have a better mechanical properties and excellent hygroscopicity. All the results show that the Kosteletzkya virginica bast fiber is one of an ideal candidate for the new textile material.

The changes in ultrastructure of leaf cell in waterlogged Kosteletzkya virginica seedlings were observed by transmission electron microscope. During waterlogging, the chloroplasts turned into a round shape and their volume was gradually reduced. Furthermore, the lamellae of thylakoids swelled, and the inclusions in chloroplast decreased. The shape of starch grains slightly changed, but their number and volume decreased, and they even disappeared in the end. On the other hand, plastoglobules enlarged and their amount enhanced gradually. The membrane and inner cristea of mitochondria gradually became unclear, while the mitochondria firstly enlarged but disappeared at the end. Similar to chloroplast, cell nucleus dwindled gradually, concentrated and tended to a round shape. Additionally, the annulate lamellae and multivesicular body occurred on the 20th day of experiment, and the cell wall distorted and twisted at the late stage of waterlogging. Consequently, these changes of organelles are the typical characteristics of the complete cell disintegration or death for Kosteletzkya virginica under long-term waterlogging.

Kosteletzkya virginica (L.) Presl. is a perennial wetland halophyte which could be exposed to heavy metals in polluted salt marsh environments. In order to investigate the interaction between salinity (50 mM NaCl) and heavy metal, young plants were exposed in hydroponic culture to 10 μM Cu in the presence or absence of 50 mM NaCl. Copper strongly inhibited the leaf emergence and lateral branch development as well as leaf expansion, and induced a significant decrease in plant dry weight (DW), water content (WC), osmotic potential (Ψs) and leaf water potential (Ψw). Copper treated plants accumulated significantly higher level of Cu in the roots than in the shoots although Cu intake rates decreased with the duration of stress exposure. Additions of NaCl in the absence of Cu excess had no detrimental impact on plant growth. In the presence of Cu excess, NaCl decreased Cu accumulation in roots and stems but had no positive impact on plant growth. Copper induced a large decrease in K concentration in roots and stems as well as a decrease in Ca concentration in the leaves. The impact of Cu and NaCl appeared to be additive on leaf Ψs and leaf quaternary ammonium compounds concentrations. It is concluded that K. virginica exhibits a high bioconcentration factor for Cu which could be, at least partly, responsible for its sensitivity to this toxic element. The impact of stress on K and Ca homeostasis is discussed in relation to ion distribution and presence of mucilage in the plant.

In this paper, the bast fibers of theKosteletzkya virginicawere degummed and separated into fine fibers, the chemical composition, morphology, microstructure and mechanical properties of the degummedKosteletzkya virginicabast fibers were characterized by means of SEM, ART-FTIR, DSC-TGA, XRD and Instron tensile tester. The results showed that the surface of theKosteletzkya virginicabast fibers was smooth, and there were many visible grooves along the vertical section. Typical celluloseⅠin theKosteletzkya virginicabast fibers was confirmed by FTIR and XRD analysis.The crystallinity of theKosteletzkya virginicabast fibers was higher than the cotton fibers and lower than the castor-oil plant bast fibers. The beginning and maximum decomposition temperature of theKosteletzkya virginicabast fibers were 252 and 347 °C respectively, which indicated that theKosteletzkya virginicabast fibers had an appropriate thermal stability. TheKosteletzkya virginicabast fibers had a better mechanical properties and excellent hygroscopicity. All the results showed that theKosteletzkya virginicabast fiber was one of an ideal candidate for the new textile material.

Recent works have shown that mixed mating systems often evolve despite strong inbreeding depression and reproductive assurance, which is one of the widely accepted explanations for the evolution of selfing. However, there have been few empirical studies on the relationship between mixed mating and reproductive assurance in perennial plants. In the herbaceous perennial, Kosteletzkya virginica , delayed selfing induced from context-dependent style curvature offers reproductive assurance, and adverse weather conditions significantly reduce pollinator visitation rates. In this study, our goals were (i) to experimentally evaluate pollinator failure rate, reproductive assurance, selfing rate and the relationships between them, and (ii) to measure inbreeding depression across multiple growth seasons. Results indicate that both population selfing rates and reproductive assurance are significantly and positively correlated with field estimates of pollinator failure rates, and there is a strong relationship between selfing rates and reproductive assurance. Inbreeding depression across multiple growth seasons ranged from 0.621 to 0.665, and there were no significant differences among different seasons. Our data demonstrates that a mixed mating system is beneficial because frequent pollinator failure has allowed reproductive assurance to evolve through delayed selfing which minimizes the risk of seed discounting and is still advantageous despite high inbreeding depression.

Curvature of un-pollinated styles towards the anthers in the Malvaceae has been interpreted as different adaptive mechanisms, presenting a challenging problem for evolutionary biologists. We have surveyed different species of this family to determine in which style curvature occurs, and to determine its possible functional roles. Two distinct types of style curvature occur in 18 species distributed in eight genera of four tribes: Type I, before pollen shedding, occurs in species of the Malvavisceae, Ureneae, and Hibisceae tribes, which have highly receptive stigmas and viable pollen when curvature brings stigmas into contact with anthers; and Type II, after pollen shedding, only appears in the protandrous species of the Malveae tribe. Curvature is often associated with annual and perennial herbs. We conclude that the adaptive significance of style curvature in the Malvaceae includes delayed selfing, promotion of outcrossing, and reduction in intrafloral male–female interference, even if the frequency of two or three of these occurs in one species only. This diversity provides model plants and the opportunity for determining the evolution, relative importance, and harmony mechanism of different adaptive significance, especially when two or three functions occur simultaneously in one floral movement of one species (e.g., Kosteletzkya virginica).

Mucilage is thought to play a role in salinity tolerance in certain halophytic species by regulating water ascent and ion transport. The localization and composition of mucilage in the halophyte Kosteletzkya virginica was therefore investigated. Plants were grown in a hydroponic system in the presence or absence of 100mM NaCl and regularly harvested for growth parameter assessment and mucilage analysis with the gas liquid chromatography method. NaCl treatment stimulated shoot growth and biomass accumulation, had little effect on shoot and root water content, and reduced leaf water potential (Psi(w)), osmotic potential (Psi(s)) as well as stomatal conductance (g(s)). Mucilage increased in shoot, stems and roots in response to salt stress. Furthermore, changes were also observed in neutral monosaccharide components. Levels of rhamnose and uronic acid increased with salinity. Staining with a 0.5% alcian blue solution revealed the presence of mucopolyssacharides in xylem vessels and salt-induced mucilaginous precipitates on the leaf abaxial surface. Determination of ion concentrations showed that a significant increase of Na(+) and a decrease of K(+) and Ca(2+) simultaneously occurred in tissues and in mucilage under salt stress. Considering the high proportion of rhamnose and uronic acid in stem mucilage, we suggest that the pectic polysaccharide could be involved in Na(+) fixation, though only a minor fraction of accumulated sodium appeared to be firmly bound to mucilage.

Emergence and early seedling growth are critical for establishing reasonable plant population densities under saline stress conditions. An experiment with seashore mallow (Kosteletzkya virginica L.) seedling culture in plastic nutrient-rich matrices and transplanted into pots filled with soil from a local farm field was conducted under five salinity levels (0, 0.3, 0.6, 0.9, and 1.2%). Emergence, survival, growth, and physiological characteristics were monitored for 45 d after seeding. Increasing salinity levels from 0.3 to 1.2% inhibited seedling growth through the reduction in leaf size, leaf number, and physiological traits. At 45 d after seeding, there was a reduction of 13 to 47% in photosynthesis, 18 to 62% in soluble protein, 6 to 84% in superoxide dismutase activity, and 20 to 81% in root activities, whereas free amino acids increased by 34 to 104%, proline by 18 to 167%, and malondialdehyde by 20 to 220%. The reduction in photosynthesis was mainly associated with the reduction in stomatal conductance. Emergence and survival rates could be maintained at ≥60% at salinity levels ≤0.9%. Our results indicate that seashore mallow could grow in saline soils with seedling culture in nutrient-rich plastic matrices and transplanted into conventional soils provided that the salinity levels in nutrient-rich medium and conventional soils are ≤0.9%.

An experiment was designed to investigate the tolerance and response of the Kosteletzkya virginica (L.) Presl to one-instar bollworms of Helicoverpa armigera (Hubner). In this experiment, the insects obviously brought an enhancement in damaged rate of leaf area (DRLA), average diameter of bitten hole (ADBH) and average grade of leaf damage (AGLD) in K. virginica seedlings. When amount of insect increased to 4 per top leaf, the average DRLA, AABH, ADBH and AGLD were 8.6%, 9.2 mm, 2.7 mm and 2.0 mm, respectively, and the seedlings showed a potential insect-tolerance to this insect stress. Furthermore, with an increase of insect density, MDA, relative permeability of membrane (RPM), O2−· production and soluble sugar concentration all enhanced, whereas activities of SOD and POD increased and subsequently declined. By statistical analysis, it was drawn that bio-toxicity of O2−· was the first destroying factor, cell membrane decomposition ranked the second, and the destruction of membrane lipid peroxidation was the slightest to K. virginica seedlings. Moreover, under the insect stress, POD was the most significant factor in protecting the seedlings, soluble sugar acted as the subordinate one, and the protection of SOD was the slightest compared to two others. In addition, insect stress obviously affected chlorophyll-fluorescence characteristics, and resulted in a significant increase in Fo and qN, and a significant reduction in Fv/Fm, ETR and qP during experiment.

Gene differential expression of Kosteletzkya virginica seedlings under salt stress at two time points (2, 24 h) in roots and leaves was analyzed using the cDNA-amplified fragment length polymorphism (cDNA-AFLP) technique. Polymorphic transcript-derived fragments (TDFs) among control plants and salt-treated plants were grouped into four main differential expression patterns: repression (A), de novo induction (B), up-regulation (C) and down-regulation (D). Among them, 34 differentially expressed gene fragments were homologous to known genes from other species and 4 were sequences with unknown functions. These differentially expressed genes can be classified into four groups according to their putative functions: (1) genes for re-establishing ion homeostasis and protecting the plant from stress damage; (2) genes involved in metabolism or energy and resuming plant growth and development under salt stress; (3) genes involved in regulation of gene expression; (4) genes for signal transduction. Changes of eight differentially expressed genes were confirmed by quantitative real time RT-PCR.

Herkogamy may act as a mechanism to reduce interference between the reproductive functions of female and male organs, but too great a distance between stigmas and anthers may also decrease the outcross pollen transfer and male and female fitness. Our goal was to quantify the effect of movement herkogamy in Kosteletzkya virginica on reproductive success and its contribution to pollen receipt and reproductive assurance. Field investigations and hand-pollination experiments were performed to test: (1) the relationship between herkogamy before curvature of un-pollinated lobes and reproductive success under pollinator exclusion; (2) the contribution of movement herkogamy to pollen receipt; and (3) the relationship between pollen load and seed set. We noted that variation in herkogamy before curvature of un-pollinated lobes did not affect the outcome of autogamous self-pollination measured by fruit set and mean number of seeds per fruit. Under natural conditions, 39% of pollen grains deposited per flower were from autogamous self-pollination via movement herkogamy resulting in contact between anthers and stigmas. The relationship between the amount of pollen grains and the number of seeds per capsule was highly significant. Flowers producing four or five seeds received more pollen grains than those producing only one seed. Our data provides experimental evidence that movement herkogamy, which decreases the separation between anthers and stigmas and results in delayed self-pollination, contributes to pollen receipt and further enhances seed set when pollinators are scarce or absent.

Kosteletzkya virginica, a perennial dicot halophytic species of the Malvaceae, is native to American salt marsh. It was introduced into China as a potential species to improve coastal wetlands and to develop ecologically sound saline agriculture. K. virginica adapts excellently to the tidal-flat habitats in China's east coast, with multiple eco-benefits; in particular, its seed oil could be used to produce biodiesel. The purpose of this study was thus to develop a standardized protocol to induce a high frequency of callus and subsequent plantlet regeneration system for a K. virginica breeding program with the final objective of applying transgenic techniques to improve seed oil yield. The embryonic axes of K. virginica were used as explants for callus induction, shoot induction from the callus and then adventitious root induction from the shoots on nine culture media with different hormone combinations. The best results were achieved on the following media: (1) 93.94% callus induction on MS medium supplemented with 1.0 mg L−1 indole-3-acetic acid (IAA), 0.3 mg L−1 kinetin, 30 g L−1 sucrose and 8 g L−1 agar; (2) 65.83% shoot induction on 1/2MS medium supplemented with 0.1 mg L−1 IAA, 0.5 mg L−1 zeatin, 30 g L−1 sucrose and 8 g L−1 agar; (3) 96.67% rooting on MS medium containing 30 g L−1 sucrose and 8 g L−1 agar. The survival rate of plantlets by organogenic regeneration was 85% after being transplanted into potting soil in flowerpots and placed in the greenhouse. This experiment indicates that we established successful callus induction and plant regeneration protocols for K. virginica.

Delayed selfing is a reproductive strategy that can increase mating opportunities and provide reproductive assurance in the absence of pollinators. When external pollination fails to occur in the herbaceous perennial, Kosteletzkya virginica, the styles curve downward to bring anthers into contact with the stigmal lobes, resulting in delayed selfing. Our goal was to evaluate experimentally the effects of weather conditions on pollinator activity, style curvature, and plant fitness. We discovered that adverse weather conditions significantly reduced pollinator visitation rates, and increased the incidence of style curvature, which resulted in delayed selfing. Furthermore, elimination of delayed selfing by experimental manipulation reduced fruit and seed set compared to non-emasculated flowers, even under adverse weather conditions. Offspring produced through selfing were similar to outcrossed progeny in the majority of fitness traits measured, and inbreeding depression was limited. Our study demonstrates that context-dependent style curvature promotes delayed selfing and provides reproductive assurance in the absence of pollinators, with minimal loss of progeny performance through inbreeding depression.

Mixed mating systems often evolve despite strong inbreeding depression, but there have been few experimental tests of this observation. Kosteletzkya virginica, a perennial dicot halophytic species of the Family Malvaceae, is native to brackish portions of coastal tidal marsh in the United States of America and was introduced into China in 1993. Pollination of K. virginica occurs through insect vectors and by delayed self-pollination via stylar movement. In the same two naturalized populations of K. virginica during 2005–2007, we measured (i) inbreeding depression across a range of life-cycle stages, (ii) pollination failure rate, and (iii) selfing rate estimated by AFLP markers. Results indicate that inbreeding depression values for the two naturalized populations during 2005–2007 ranged from 0.620 ± 0.036 to 0.656 ± 0.032, and mean inbreeding depression was 0.640 ± 0.006. Pollinator failure rates at the two naturalized K. virginica populations during 2005–2007 ranged from 0.091 ± 0.039 to 0.174 ± 0.061, and selfing rate ranged from 0.247 ± 0.018 to 0.468 ± 0.031. Population selfing rates are significantly and positively correlated with field estimates of pollinator failure (P = 0.008

Kosteletzkya virginica, a perennial halophyte, is native to the American salt marsh. It was introduced into China as a potential species to improve tideland and develop ecologically sound saline agriculture. The experimental results in the fields over 10 years indicated that K. virginica adapts excellently to the tidal flat habitats in China's east coast, with multiple ecobenefits such as landscape beautification, revegetation and providing food source for targeted wildlife or migratory birds. Seed yields of unselected mixed and bred lines were 621kg/ha and 957kg/ha, respectively. Oil contents in the seeds of the unselected mixed and bred lines were 17.536% and 20.64%, respectively. The unsaturated fatty acids (70.134%) in the seed oil predominated over the saturated ones (29.866%). Seed oil of K. virginica could produce a high quality biodiesel, of which the unsaturated C18 content of the main part was about 68.62% and sulfur content was 0.0003%. Cetane No. and flash point were both higher than those of diesel fuel, and rust class of steel was lower than that of diesel fuel. These indicate that K. virginica could be used as an agroecoengineering species for alternative agricultural production and for revegetation of salt-affected tidal flats in China's east coast.

Kosteletzkya virginica(L.) is a newly introduced perennial halophytic plant. Presently, reverse transcription quantitative real-time PCR (qPCR) is regarded as the best choice for analyzing gene expression and its accuracy mainly depends on the reference genes which are used for gene expression normalization. In this study, we employed qPCR to select the most stable reference gene inK. virginicawhich showed stable expression profiles under our experimental conditions. The candidate reference genes were 18S ribosomal RNA (18SrRNA),β-actin (ACT),α-tubulin (TUA), and elongation factor (EF). We tracked the gene expression profiles of the candidate genes and analyzed their stabilities through BestKeeper, geNorm, and NormFinder software programs. The results of the three programs were identical and18SrRNAwas assessed to be the most stable reference gene in this study. However,TUAwas identified to be the most unstable. Our study proved again that the traditional reference genes indeed displayed a certain degree of variations under given experimental conditions. Importantly, our research also provides guidance for selecting most suitable reference genes and lays the foundation for further studies inK. virginica.

A new naphthalene, 8-methoxy-2,7-dihydroxyl-4-(1'-hydroxyl-isopropyl)-6-methyl-1-naphthaldehyde, together with twelve known compounds were isolated from the tubers of Kosteletzkya virginica. Their structures were elucidated by spectroscopic methods, including 1D-, 2D-nuclear magnetic resonance (NMR) and high-resolution time of flight electrospray ionization mass spectrometry (HRTOFESIMS). Some compounds were evaluated for their potential in scavenging diphenyl-picryl hydrazyl radical (DPPH•), inhibition of nitric oxide (NO) induced by lipopolysaccharide (LPS), and cytotoxic activity. The new compound showed activities against DPPH•, NO, human acute promyelocytic leukemia (HL-60) and human colorectal adenocarcinoma (LOVO), with IC50 of 34.6, 12.5, 40.5, 31.7 μmol L-1 respectively.

A new naphthalene, 8-methoxy-2,7-dihydroxyl-4-(1'-hydroxyl-isopropyl)-6-methyl-1-naphthaldehyde, together with twelve known compounds were isolated from the tubers of Kosteletzkya virginica. Their structures were elucidated by spectroscopic methods, including 1D-, 2D-nuclear magnetic resonance (NMR) and high-resolution time of flight electrospray ionization mass spectrometry (HRTOFESIMS). Some compounds were evaluated for their potential in scavenging diphenyl-picryl hydrazyl radical (DPPH•), inhibition of nitric oxide (NO) induced by lipopolysaccharide (LPS), and cytotoxic activity. The new compound showed activities against DPPH•, NO, human acute promyelocytic leukemia (HL-60) and human colorectal adenocarcinoma (LOVO), with IC50 of 34.6, 12.5, 40.5, 31.7 μmol L-1 respectively.